Machine tool



Dec. 3, 1968 E. A. THOMPSON 3,413,807

MACHINE TOOL Original Filed Dec. 30, 1963 ll Sheets-Sheet 1 INVENTOR.EARL A.THOMPSON Y afigm ATTORNEY,

Dec. 3, 1968 E. A. THOMPSON MACHINE TOOL ll Sheets-Sheet 2 OriginalFiled Dec. 30, 1963 INVENTOR. EARL A. THOMPSON a; mag Q ATTORNEY Dec. 3,1968 E. A. THOMPSON MACHINE TOOL 11 Sheets-Sheet 3 Original Filed Dec.30, 1963 INVENTOR- EARL A. THOMPSON FIG. 3

ATTORNEY Dec. 3, 1968 E. A. THOMPSON MACHINE TOOL ll Sheets-SheetOriginal Filed Dec. 30, 1963 I N VE N TOR. EARL A. THOMPSON BY A K/K- ZWATTORNEY Dec. 3, 1968 E. A. THOMPSON 3,413,307

MACHINE TOOL Original Filed Dec. 30, 1965 ll Sheets-Sheet 5 INVENTOR.EARL A. THOMPSON KXW ATTOR N EY MACHINE TOOL ll Sheets-Sheet OriginalFiled Dec. 30, 1965 INVENTOR. EARL A. THOMPSON FIG. 6

J {KW ATTORNEY Dec. 3, 1968 E. A. THOMPSON 3, 7

MACHINE TOOL Original Filed Dec. 30, 1965 ll Sheets-Sheet 7 INVENTOR.EARL A. THOM PSON FIG. 7 BY /1 ATTORNEY Dec. 3, 1968 E. A. THOMPSONMACHINE TOOL Original Filed Dec. 30, 1963 11 Sheets-Sheet 8 FIG. 8

INVENTOR. EARL A. THOMPSON ATTORNEY Dec. 3, 1968 THOMPSON 3,413,807

MACHINE TOOL Original Filed Dec. 30, 1963 ll Sheets-Sheet '9 FIG. 9

I NVEN TOR. EARL A. THOMPSON BY J- K? 645% ATTORNEY Dec. 3, 1968 E. A.THOMPSON 3,413,807

MACHINE TOOL Original Filed Dec. 30, 1963 ll Sheets-Sheet 10 P16. IO

INVENTOR. EARL A THOMPSON BY J- Q4? 5am ATTORN EY E. A. THOMPSON3,413,807

MACHINE TOOL $50, 1963 11 Sheets-Sheet ll INVENTOR. EARL A. THOM PSONATTORNEY Dec. 3, 1968 iginal Filed Dec.

nited States Patent 3,413,807 MACHINE TOOL Earl A. Thompson, BloomfieldHills, Mich., assignor to Earl A. Thompson Manufacturing Co., acorporation of Michigan Continuation of application Ser. No. 334,503,Dec. 30, 1963. This application Jan. 30, 1967, Ser. No. 621,092

17 Claims. (Cl. 60-54.5)

ABSTRACT OF THE DISCLOSURE A tool, e.g. a grinding wheel, isreciprocated by either of two hydraulic link actuators, the pulsators ofwhich may be constantly operated by cams against a return pressure. Oneactuator may provide a long stroke, e.g. to remove the grinding wheelfrom the work and insert it in a new work piece. The other actuator mayoscillate the wheel rapidly on a short stroke in the work piece while itis grinding. The actuators are selectively made operative or inoperative(while their pulsators are continuously cycled) by confining liquid tothe appropriate hydraulic circuit or permitting the liquid to surge intoand out of the circuit. This latter is accomplished by a single ballvalve moved to one of two positions by a third hydraulic actuatoragainst a return spring.

This application is a continuation of my application Ser. No. 334,503filed Dec. 30, 1963 which is abandoned.

This invention relates to machine tools and particularly to anoscillator for moving a part, such as a tool carriage back and forth. Itis particularly, but not exclusively, suitable for oscillating thegrinding wheel of an internal grinder, for example as disclosed in myUS. Patent 3,218,760 issued Nov. 23, 1965. The invention includesimprovements on the devices disclosed in this and in my US. Patents3,003,292 and 3,071,929, the disclosures of all of which areincorporated herein by reference.

In such grinders a rotating grinding wheel is mounted on a head or slidewhich moves the wheel into and out of longitudinal grinding positionwithin the rotating work piece, oscillates the wheel longitudinally overthe Work on a short stroke While rough grinding, withdraws the wheel fordressing, reinserts it for finish grinding, and (after grinding a numberof work pieces) withdraws the worn wheel from the work for replacement.The slide is then oscillated through a long stroke over a diamond todress the new wheel to proper size, roundness and alignment before theslide finally inserts the wheel again into I the work.

In my Patent 3,218,760, and in Patent 3,003,292, I have disclosedoscillators for the grinding wheel including various forms of constantvolume, liquid column motion transmitters which have an actuator or pumppiston moved by a cam and a follower piston moved by the liquid which ismoved by the actuator piston. While these oscillators operatesatisfactorily within their inherent limitations, I have discovered thatvarious improvements can be made and I have invented new forms ofactuating and control mechanisms which reduce or eliminate variousdisadvantages of prior known devices.

For example in 3,003,292 there is a single actuator piston driven by apush-pull rod which is mechanically brought into operative relationshipwith either of a pair of constantly rotating cams by moving either caminto or out of contact with a cam follower which drives the push-pullrod. Each cam performs one of the two required oscillation cycles. Inthe light of subsequent developments this is a relatively awkward andexpensive device and subject to various undesirable errors.

Both of the known oscillators referred to are inconvenientlyincorporated in the grinder, and are not as adapted as is desirable tobe used.

In US. Patent 3,218,760 valves have been substituted for the mechanicalshifting arrangement of 3,003,292, but this is complicated and expensiveand has other disadvantages.

One of the objects of the invention is to provide an improved oscillatorwhich is simple, reliable, precise and compact and can be readilyadapted to various designs of grinder, and especially to provide aunitary package of oscillator, drive motor and controls.

Another object is to provide an improved compact and efiicientarrangement of cams, cam followers and actuating devices driven therebyfor operating actuators, especially, but not necessarily, pulsators ofthe confined liquid column type.

Another object is to provide an improved single acting pulsatorconstantly connected to a carriage motor and constantly driven whilebeing rendered operative or inoperative selectively by confining itsliquid to constant volume or permitting its liquid to change volume, andespecially to provide an improved valve and improved controls thereforfor confining the liquid in the oscillator circuit or permitting theliquid to change volume while the actuator of the oscillator isoperating.

Another object is to provide an improved control valve for rendering arunning oscillator operative or not which valve is not subject toleakage outside the system, particularly such a valve in a system usinga control pressure and oscillating pressure, both superior to anopposing return pressure, arranged to direct any leakage into the returnportion of the system Another object is to provide an improvedoscillator for dressing a grinding wheel combined with a simple positiveand reliable control for rendering the oscillator operative or not whilethe oscillator is constantly being driven from a power source.

Another object is to provide an improved oscillator for dressing agrinding wheel combined with a simple, effective and precise control ofthe position of the dressing tool, coordinated with the dressingoscillator.

Another object is to provide an improved dressing tool feed actuatormoved either in response to oscillation of a grinding wheel at onegeneral location or in response to non-oscillating rectilinear movementof the wheel into or out of grinding position in a work piece.

Another object is to provide a double-acting hydraulic motor for placinga tool carriage and a control for selectively directing biasing pressureto either end of the motor while directing positioning pressure oroscillating pressure to the other end.

Another object is to provide an improved single acting pulsator oractuator for advancing or retracting a tool carriage against a biasingor return force and to provide separate single acting pulsators foroscillating the carriage at different times in its cycle and bydifferent modes of oscillation, against a constant biasing or returnpressure.

Another object is to provide a pair of single acting pulsators foroscillating the tool carriage at different times and by different modesof oscillation, which pulsators are constantly connected hydraulicallyto a carriage motor but are rendered operative selectively by improvedhydraulic apparatus.

Other objects and advantages of the invention will be apparent from thefollowing description and from the accompanying drawings, in which eachreference character always designates the same part whenever it occurs.

In the drawings:

FIG. 1 is a perspective of one form of internal grinder having anoscillator embodying one form of the invention.

FIG. 2 is a structural section, arranged schematically, of the grindingwheel carriage as seen from the front of the grinder of FIG. 1.

FIGS. 3 to 6 are diagrams of the oscillator mechanism and its controlsin various conditions of operation, FIG. 3 representing the grindingwheel in its grinding position but not oscillating.

FIG. 4 represents the oscillator with the grinding wheel in grindingposition and being oscillated through a short grinding stroke by one oftwo pulsators.

FIG. 5 represents the grinding wheel retracted from the grindingposition to be dressed for final finish grinding.

FIG. 6 shows the apparatus when dressing a new wheel, the wheel beingretracted from grinding position and being oscillated through a longdressing stroke by the other pulsator.

FIG. 7 is a section on the line 77 of FIG. 2, partly broken away.

FIG. 8 is a section on the line 88 of FIG. 2, partly broken away.

FIG. 9 is a section on the line 99 of FIG. 7.

FIG. 10 is a section on the line 10-10 of FIG. 8, and

FIG. 11 is a section on the line 1111 of FIG. 10, partly broken away.

FIG. 12 is an enlarged portion of FIG. 10 showing a section of a valve.

Referring to FIGS. 1 and 2, the grinder may be constructed in general asshown in my Patent 3,218,760. It includes a rotatable work holder 20driven by a motor. The grinding wheel 22 is mounted on a spindle drivenby a hydraulic turbine 23 supplied by fluid pressure hoses 24. Theturbine and grinding wheel are mounted on a sliding carriage 26 shown ingreater detail in FIG. 2. The carriage slides on an upper guide rod 28fixed in the frame 30 of the grinder and is clamped to a lower guide rod32 which slides in bearings in the frame.

The carriage and lower rod 32 are moved toward and away from the work byan oscillator designated as a whole by 33, which is the subject of thisinvention.

The oscillator includes an oscillator rod 34 fastened to the carriageand connected to a piston 36 slidable between adjustable stops 38 and 40in a cylinder 42 which the piston divides into a rod end retractingchamber 44 and a head end of advancing cylinder 46.

In each of FIGS. 3 to 6 broken lines indicate parts of the apparatusthat are inactive during the particular conditions depicted by theparticular figure. An arrow, whether solid or broken, indicates that thecam to which it is applied is rotating. In each of these four figuresthe pipes and chambers are coded to indicate the condition and pressuretherein. In this code indicates pulsating oil producing oscillation ofthe piston 36. H indicates oil which is functioning in an actuator orpulsator, for example to hold a part in a fixed position to serve asreaction, or to move oil to exert a constant or varying pressure to movea part. RO indicates oil at accumulator pressure, called return oil anddesignated R0 in this description. V indicates that the line or chamberis vented to the atmosphere. indicates oil under pressure from anysuitable supply for operating a clutch shifting mechanism. This may beeither R0 or oil from any suitable source of appropriate pressure.

Referring to FIGS. 3 to 6, the piston 36 is advanced toward the work bysuperior pressure of oil in the head end 46 and is retracted by superiorpressure in the rod end 44. It is oscillated by maintaining a constantreturn pressure in the head end while cyclically varying the pressure inthe rod end above and below the return pressure. Return pressure issupplied from a pressure reservoir or expansible accumulator 50containing a body 52 of oil held under substantially constant pressureby air in a chamber 54 supplied by a pump 56 and separated from the oilby a piston 58.

The accumulator constantly supplies R0 by a conduit 60 to a valve 62which may direct RO either to the head end of the cylinder 42 by aconduit 64 or to the rod end by a conduit 66. The valve includes a ball68 constantly urged by a return spring 70 toward a return seat 72. Whenthe ball is on this seat RO exerts pressure (from conduit 60 throughchamber 67 of the valve and conduit 66) in the rod end 44 of thecylinder to urge the piston 36 away from the work, that is to the rightas seen in FIG. 3. The ball 68 may be held off the return seat 72 and(for oscillation) against a seat 74 by a pin on a piston 76 forming partof an oscillator control actuator generally designated 78. The pistonslides in a cylinder 79 forming part of the valve 62, and divides thiscylinder into an oscillator control chamber 82 and a passage chamber 80.The control chamber 82 forms part of the oscillator control actuator 78,which also includes the pipe 84 connecting chamber 82 to anotheractuator chamber 86 closed by a piston 88 which is moved cyclically by acam 90 on a constantly rotating shaft 92. The oscillator controlactuator or pulsator 78 is a confined liquid motion transfer device asis known, as more fully described in my US. Patent 3,071,929.

The shaft 92 also drives a cam 94 forming part of a wheel head actuatordesignated as a whole by 96 which includes an actuating chamber 98connected to pipe 64. for moving and holding the piston 36. The piston36 may be oscillated by either of two pulsators and 112 built likeactuators 78 and 96 but operating at higher frequency. They areconstantly connected hydraulically to rod end 44, but are made operativeselectively.

The normal grinding pulsator 110 includes a cylinder 380 and is driven'by a earn 114 on a shaft 116 rotated at times by a normally engagedclutch 118 from a constantly rotating shaft 120 driven by a motor belt122. The pulsator 112, which is for dressing a new wheel, includes acylinder 111 driven from the same shaft 120 whenever the machinereleases the clutch 118 engages another clutch 124 mechanicallyconnected to clutch 118 by connection 126, as will be explained.

FIG. 3 shows the apparatus when the grinding wheel has just beenadvanced into grinding position within the work (which is out of contactwith the wheel).

The closed circuit of the wheel head actuator 96 is formed by the headend chamber 46, pipe 64, chamber 98, and chamber 80 when closed byseated ball 68. The force of RO pressure on the left of the ball and theforce of the spring 70 together hold the ball seated against pressuredeveloped by the wheel head actuator 96 as the cam 94- rotates to theposition in which it has pushed the piston 36 against R0 pressure andholds the piston 36 in the position shown in FIG. 3.

The grinding oscillator cam 114 is rotating as indicated by the arrowwhich means that the piston in grinding pulsator 110 is beingoscillated. However the wheel is not being oscillated because thepulsator 110, which is connected to the chamber 67 of the valve 62 bythe pipe 128, cannot develop pulsating pressure in the rod end chamber44, since the accumulator 50 is connected to the pipes 66 and 128through the pipe 60 and the chamber 67. Consequently oscillation of thepiston in grinding pulsator 110 merely pumps oil into and out of theaccumulator against the constant pressure of the air in chamber 54. Thisprevents any change of pressure in the rod end chamber 44.

FIG. 4 shows the position of the apparatus a moment later than FIG. 3.The oscillator control actuator 78 has become active as indicated bysolid lines, due to rotation of the cam 90 to the position whichadvances the piston 88. This forces oil into the chamber 82, forcing thepiston oscillator control 76 to the left and moving the ball 68 againstthe force of the return spring 70 and holding it on the oscillating seat74.

A force-multiplying free piston 130 having a portion of small diameterin a cylinder 132 and a portion of large diameter in a cylinder 134 isconnected to the pipe 84 by a pipe 136. This piston is in its lowermostposition against the bottom of the cylinder 134. It confines oil in thecircuit of the oscillator control actuator 78 and serves as a reactionto permit the cam 90 to move and hold the piston 76 to the left.

The wheel head cam 94 continues to hold the piston of the wheel headoscillator 96 to the left and maintain the position of piston 36.

As soon as the ball is seated on the oscillating seat 74 the pipe 60 iscut off from communication with the chamber 67 and with the pulsatorpipe 128 so that this latter pipe is now connected through chamber 67and pipe 66 directly to the rod end chamber 44. Oscillation of thepiston in grinding pulsator 110 now exerts pulsating pressure in the rodend, to oscillate the wheel. This varying pressure is maintained againstthe reaction point of the piston in new wheel dressing pulsator 112.This pulsator is connected into the oscillating circuit by pipe 138. Itsstationary cam 140 now holds its piston.

Also the accumulator pipe 60 is connected through the chamber 80 to thepipe 64 and to the head end chamber 46 so that RO pressure is maintainedin the head end. Since this pressure is supplied by the expansibleaccumulator the oil in the pipe 64 is not confined. Consequentlywhenever the pressure in the pipe 128 rises above RO pressure the piston36 is moved to the right and Whenever the oil pressure in pipe 128 fallsbelow R pressure the piston 36 is moved to the left.

The form of the grinding oscillator cam 114, the speed of the shaft 116and the diameter of the piston in the grinding oscillator 110 arecoordinated so that the wheel is oscillated through a short stroke,which might he for example a few thousandths of an inch, and at thedesired frequency. During this phase of the operation the work is slowlyadvanced against the face of the wheel for a predetermined time until ithas been rough ground to the desired size. This is done by any suitableapparatus, as disclosed for example in my Patent 3,218,760.

At the end of the predetermined grinding period the wheel head actuatorwithdraws the wheel from the work for a light dressing preparatory tofinal finish grinding. FIG. shows this condition. The oscillator controlcam 90 has receded to permit the ball 68 to seat on the return seat 72,making the oscillator control actuator 78 inactive, although its cam 90continues to rotate. The seating of the ball closes the wheel headactuator circuit formed by the head end 46 and cylinder 98 of wheel headactuator 96. The cam 94 has receded to provide room in the head end 46to permit RO, now in the rod end via pipes 60 and 66 and valve chamber67 to move the piston 36 to the intermediate position shown in FIG. 5.This withdraws the wheel from the work and across a diamond dressingtool as disclosed in my U.S. Patent 3,218,760. The grinding pulsator 110continues to oscillate but merely surges R0 as shown by R0 in itscircuit in FIG. 5.

Each time the wheel is withdrawn to be dressed for finish grinding, thediamond dressing tool is fed toward the wheel. This may be just beforethe wheel is withdrawn, or just before it is advanced again, or both.The diamond is fed forward the required precise distance by a ratchet150 moved forward by a piston in a cylinder 152 connected to a pipe 153and forming part of a diamond feed impulse actuator 154 operated by acam 156 on camshaft 92. This actuator is made like the other actuatorsherein and its cam is timed to operate the ratchet each time the wheelhead actuator 96 withdraws the wheel for dressing. The ratchet and itsoperating piston in cylinder 152 are returned by R0 in a return cylinder158. Thereafter wheel head cam 94 returns its piston to the left,returning the piston 36 to the grinding position of FIG. 3, and afterthe wheel has been dressed, the oscillator control actuator 78 movesball from return seat 72 6 to oscillating seat 74, and oscillatingresumes as shown in FIG. 4 for the finish grinding.

After each work piece is finished, automatic controls for example asdisclosed in Patent 3,218,760 may retract the wheel, remove the finishedwork piece, insert a new work piece in the work holder and return thewheel to grinding position, FIG. 3.

Eventually the wheel wears out. Then an automatic signal, not shown,indicates the condition, and neither the operator or an automaticcontrol stops the machine with a cycle stop switch which assures thatthe machine stops with its cam shafts in predetermined positions. Theoperator then puts a new wheel on the turbine spindle. This new wheelmust be dressed precisely to the required size, roundness and alignment.For dressing, the wheel is oscillated across the diamond dressing toolthrough a long stroke which includes the entire length of the Wheel andthe diamond is fed forward once for each stroke or each cycle, as may bepreferred. This is done by the apparatus in the condition shown in FIG.6.

The machine has stopped with the piston 36 in an appropriate position todress the wheel, indicated in FIG. 6. When the machine is started again,the cam shaft 92, which rotates constantly during the grindingoperation, as described above, is now still. Also a clutch-shiftingmotor including a piston 160 in a cylinder 161 has heretofore beenvented by the pipe 162, spring-closed valve 164 and vent port 168, asshown in FIG. 5. Now a solenoid is energized to raise valve 164 from theposition of FIG. 5 to the position of FIG. 6. This closes the vent 168and Opens the valve to connect line 162 to a source of pressure 172 topressurize the motor 160 which then engages clutch 124 and disengagesthe clutch 118. This shifting of clutches permits shaft 116 to stop androtates shaft 174 which rotates cam 140 to drive wheel dressingoscillator 112. Pressurizing the pipe 162 also lifts the free piston 130to cause a pressure impulse in pipe 136. Due to the reaction of thestationary piston 88, this moves the ball 68 off the return seat 72 andholds it on the oscillating seat 74. R0 enters the head end chamber 46,and wheel dressing oscillator 112, connected in a confined-volumecircuit with the rod end chamber 44 through valve chamber 67 and pipes66, 128 and 138, now oscillates the piston 36 through a long stroke, asdetermined by the displacement of the oscillating piston.

The diamond dressing tool, which is part of the grinder shown in FIG. 1,is mounted in a holder which is pivoted on a shaft and moved by apressure cylinder into or out of the path of the wheel, as disclosed inmy U.S. Patent 3,218,760. When a new wheel is to be dressed, the diamondmust be pivoted into the path of the wheel. This is done by connectingsaid cylinder of said patent, herein represented as 176, to the line162. Whenever the line 162 is pressurized, that is whenever the wheeldressing shaft is rotated, the diamond is placed in dressing position.Whenever the line 162 is vented, the diamond is moved out of the way.

After each pass of the wheel under the diamond tool in dressing thewheel the diamond is advanced to dress the wheel on the next stroke.This is done by a second diamond feed actuator driven by a cam 182 onthe cam shaft 174 and connected to pipe 153. This is timed so that afterevery stroke of the wheel dressing oscillator 112 the actuator 180operates one stroke to advance the ratchet 150. At this moment thefinish-dress-diamond-feed actuator 154 is held by its cam 156 and formsthe reaction point for the impulse of actuator 180.

In confined liquid column actuators it is customary to have in thecolumn, when the cam begins its advance, a greater volume of liquid thanis required for the positive and precise displacement of the actuatedpart. This assures precise displacement in spite of any loss of liquidby leak. The cam continues to rise after the part has reached the limitof its movement, and this suddenly increases the pressure in theactuator circuit to blow off the excess volume of oil through a reliefvalve. In the case of wheel head actuator 96 the ball 68 seated on seat72 by spring 70 acts as a relief valve when piston 36 reaches left handstop 40. On the return stroke which withdraws the wheel to insert a newworkpiece the cam 94 continues to fall or withdraw after the piston 36reaches the limit of its stroke at right hand stop 38, and the pressurein pipe 64 falls below RO pressure in pipe 60. This opens a replenishingcheck valve 190 to fill the circuit again to its original excess volume.

Other actuator circuits may be connected to balance valves, not shown,but each including a relief valve and a replenishing check valve asdisclosed for example in FIG. of my Patent 3,071,929.

If the pressure in the circuit of oscillator 110 or 112 should fallbelow a predetermined value, such as 50 psi, indicating leakage, RO canmake up the loss through a replenishing check valve 192.

After the new wheel has been dressed, the wheel is advanced to grindingposition and oscillated there, as shown consecutively in FIGS. 3 and 4and described above. This requires shifting the clutches 118, 124 bydeenergizing the solenoid 170 to let valve 164 drop to vent clutch motorline 162. This stops shaft 174, and it is important to have this shaftstop in a predetermined position, for example after the completion of anew wheel dressing stroke and before the diamond is advanced again. Toaccomplish this a normally closed stop switch 194 is included in thecontrol circuit of solenoid 170, which switch must be opened tode-energize the solenoid. This switch is opened by a cam 198 on thewheel dressing shaft only when this shaft is in the desired position.

FIGS. 7 to 11 show one form of actual structure of some of the principalelements of the oscillator 33. As shown in FIG. 1 the casing containingthe oscillator is mounted on the frame 30 of the grinder, generally inline with the sliding carriage support 32. A motor 300 (FIGS. 1, 7)attached to the bottom of the casing supplies the motive power for theoscillator, except for the cam shaft 92 which is part of a cam shaft inthe grinder shown in FIG. 1. The motor 300 drives the oscillator throughthe belt 122 which rotates an input pulley 302 mounted on the constantlyrotating input clutch shaft 120 (FIGS. 3, 9) which lies in a planeperpendicular to the direction of travel of the carriage 26. This shaftcarries one member of each of the clutches and two worm wheels whichdrive the grinding and wheel dressing oscillator shafts.

Referring to FIG. 9, the shaft 120 has pinned to it a central doublemale cone clutch member 304 which, when held to the right by spring 306as FIG. 9 is seen, engages the female cone clutch member 118 to drivethe grinding oscillator shaft, and when held to the left, against theforce of the spring by pressure in chamber 161, engages the female coneclutch member 124 to drive the wheel dressing oscillator shaft. Eachfemale cone is part of a sleeve journaled in radial and thrust bearingsin a sleeve 310 fixed in the casing 312 of the oscillator. The grindingoscillator clutch sleeve 118 is formed with a worm 314 which engages aworm wheel 316 (FIG. 10) keyed to an intermediate shaft 318, to theright end of which is keyed an intermediate gear 320 (FIGS. 10, 11)driving an oscillator cam shaft gear 322 keyed to the grindingoscillator cam shaft 116 (FIGS. 3, 11). The oscillator cam 114 is keyedto this shaft 116, FIGS. 9, 10.

Wheel dressing clutch sleeve 124 is formed with a worm 324 which engagesa worm wheel (cut off from view by the location of section line 1010).This worm wheel is like worm wheel 316 (FIG. 10) and is keyed to asecond intermediate shaft 326 (FIGS. 9, l1) keyed to a secondintermediate gear 328 (FIG. 11) meshing with a driving gear 330. Thislatter is keyed to the wheel dressing cam shaft 174 having the wheeldressing oscillator cam 140 and the diamond feed cam 182 keyed thereto.As shown in FIGS. 3, 9, 11, a roller cam follower 332 for wheel dressingcam 140 is journaled on a pin 334 journaled in bearings in the split endof a fork 336, the other end of which fork is journaled on intermediateshaft 318. Also journaled on the pin 334 and between the legs of thefork 336 is a forked piston rod 338 straddling the cam follower. Thepiston rod is fixed to a piston 340 sliding in the cylinder 111 of thewheel dressing oscillator 112. The piston may be made and related to thecylinder as disclosed in FIG. 22 of my Patent 3,071,929. Theintermediate shaft 318 has journaled on it a similar fork 344 the splitend of which carries a pin 346 on which are mounted a piston rod 348 anda roller follower 350 which latter rides on the diamond feed cam 182(FIGS. 3, 10). Piston rod 348 is fixed to a piston made like piston 344and sliding in the cylinder of diamond feed actuator 180 (FIG. 3).

The other intermediate shaft 326 (FIG. 9) carries fork 360 like theother forks having at its split end a piston rod 362 straddling a rollercam follower 364 journaled on a pin 366 and riding on the grindingoscillator cam 114. Piston rod 362 is fixed to a piston like the otherpistons described which forms part of the grinding oscillator 112.

As shown in FIG. 10 the casing of the oscillator 33 has a thick portion370 in the upper face of which is a large bore 372 to receive a plug orplate 374 forming the bottom of the accumulator and bolted to the part370. In the bottom of the large bore and below the plate are varioussmall bores which receive the valve 62 and various liners which form thecylinders of the actuators 110, 112 and 180. The valve 62 is placed in abore 376. The outlines of the cylinder liners in the remaining bores areshown in broken lines in FIG. 8. Cylinder 111 is part of wheel dressingoscillator 180. Cylinder 378 is the diamond feed cylinder of actuator180; 380 is the cylinder of oscillator 110. The plate 374 closes theends of these cylinders and is sealed to form pumping chambers for theactuators. The various control and actuator passages previouslyidentified are also formed in the plate 374 and thick part 370 of thecasing by suitable coring and/or drilling and blocking as known in theart and as indicated by previously mentioned reference characters inFIGS.

FIG. 12 shows one form of construction and arrangement of the valve 62.A rectangular boss 384 is formed integral with plate 374 and has athrough bore 386 matching the valve bore 376. The valve is placed inthese two bores. The valve includes a first liner 388 having the chamber67 inside it, and is grooved and pierced to provide parts of theoscillator passages 66 and 128. A second aligned liner 390 includes theoscillating seat 74 and is grooved and pierced to provide part of the R0passage 60. These two liners are in alignment with a third liner 392which includes the return seat 72, a space forming the chamber 80, andthe cylinder 79 holding the piston 76. The liner 392 is grooved andpierced to form part of the passage 64 connected with the chamber 80.The piston has a pin 394 for moving the ball off of seat 72 and holdingit on seat 74. The cylinder 82 is closed by a bottom plate 396 bolted tothe thick part 370 of the casing. This plate holds the valve assembledfrom the bottom. The valve is sealed and held assembled from the top bya top plate 398 bolted to the boss 384 and confining the compressionspring 70 against a spring cup 400 which carries a pin 402 for urgingthe ball toward return seat 72. The spring cup is confined by a stopring 404. The top plate is pierced by a passage 406 which admits RO fromthe accumulator to the chamber 67 under control of the ball check valve192 normally seated by spring 408.

FIGS. 7, 10 show the construction and arrangement of the cam 198 carriedby wheel dressing cam shaft 174 for operating switch 194 to assurede-energizing of solenoid at the proper time to stop the shaft 174 inproper position.

The oscillator is contained in a unitary casing which can be readilybolted to an existing grinder as shown in FIGS. 1 and 2 with itsoscillating cylinder 42 aligned with the direction of travel of thewheel carriage. The cam shafts 116 and 124 and lay shafts 318 and 326that drive them are parallel to this cylinder and below it in thecasing. The rocker arms 336 and 344 are pivoted on one lay shaft 318 sothat their cam followers ride on the cams on the opposite cam shaft 326not driven by the shaft 318.

Similarly the rocker arm 360 is journaled on the other lay shaft 326 andits cam follower rides on cam 114 on the opposite shaft not driven bylay shaft 326. This has advantages of economy, compactness andefiiciency not found in prior known oscillators.

This compactness and efiiciency are further enhanced by the arrangementin the same casing of the extremely simple valve 62 and the variouspistons and control passages. The accumulator 50 is formed by a domebolted to the casing over the valve 62 so that one end of the valve isplaced in the oil in the accumulator. This simplifies passages andconnections.

The valve itself is simple and efiicient. Any leakage of control oilfrom the high pressure side (either pipe 64 or chamber 67) past thevalve seats must flow into the lower pressure accumulator circuit andsuch leakage is made up automatically from the accumulator byreplenishing valves. The valve is controlled by moving parts entirelysealed within the valve casing so that no leakage outside the casing dueto movement of control parts can occur.

1. An oscillator for cyclically moving a part back and forth comprisingin combination a pressure cylinder having movable end wall meansdefining an advancing chamber, a second pressure cylinder having movableend wall means defining a retracting chamber, a source of liquidpressure, a first liquid column actuator having its liquid circuitconnected to one chamber, a second liquid column actuator having itsliquid circuit connected to the other chamber, each of said actuatorscyclically developing a pressure greater than the pressure of saidsource, and a valve for controlling the end wall means, said valveincluding means defining three spaces, the first space being constantlyconnected to one of said chambers, the second space being constantlyconnected to the other of said chambers and the third space beingconstantly connected to said source, and means movable to a firstposition for establishing communication betwen the first and thirdspaces while preventing communication between the second and thirdspaces, and movable to a second position for establishing communicationbetween the second and third spaces while preventing communicationbetween the first and third spaces.

2. An oscillator for cyclically moving a part back and forth comprisingin combination a pressure cylinder having movable end wall meansdefining an advancing chamber, a second pressure cylinder having movableend wall means defining a retracting chamber, a source of liquidpressure, a first liquid column actuator including a continuouslyoperatable hydraulic impulse generator and having its liquid circuitpermanently connected to one chamber, a second liquid column actuatorincluding a hydraulic impulse generator and having its liquid circuitpermanently connected to the other chamber, a continuously rotatableoperator for the second impulse generator, each of said actuatorscyclically developing a pressure greater than the pressure of saidsource, a valve movable to two positions, in one of which it connectssaid source to the first actuator circuit and confines the liquid in thesecond actuator circuit, and in the other of which posi tions itconfines the liquid in the first actuator circuit and connects saidsource to the second actuator circuit, and means responsive to theangular position of the operator for moving the valve from one positionto the other.

3. An oscillator for cyclically moving a part back and forth comprisingin combination a pressure cylinder having movable end wall meansdefining an advancing chamber, a second pressure cylinder having movableend wall means defining a retracting chamber, a source of liquidpressure, a first liquid column actuator having its liquid circuitconnected to one chamber, a second liquid column actuator having itsliquid circuit connected to the other chamber, each of said actuatorscyclically developing a pressure greater than the pressure of saidsource, and a valve movable to two positions, in one of which itconnects said source to the first actuator circuit and confines theliquid in the second actuator circuit, and in the other of whichpositions it confines the liquid in the first actuator circuit andconnects said source to the second actuator circuit.

4. An oscillator for cyclically moving a part back and forth comprisingin combination a pressure cylinder having movable end wall meansdefining an advancing chamber, a second pressure cylinder having movableend wall means defining a retracting chamber, a source of liquidpressure, a first liquid column actuator including a continuouslyoperatable hydraulic impulse generator and having its liquid circuitpermanently connected to one chamber, a second liquid column actuatorincluding a continuously operatable hydraulic impulse generator andhaving its liquid circuit permanently connected to the other chamber,each of said actuators cyclically developing a pressure greater than thepressure of said source, and a valve movable to two positions, in one ofwhich it connects said source to the first actuator circuit and confinesthe liquid in the second actuator circuit, and in the other of whichpositions it confines the liquid in the first actuator circuit andconnects said source to the second actuator circuit.

5. An oscillator for cyclically moving a part back and forth comprisingin combination a pressure cylinder having movable end wall meansdefining an advancing chamber, a second pressure cylinder having movableend wall means defining a retracting chamber, a source of liquidpressure, a first liquid column actuator having its liquid circuitconnected to one chamber, a second liquid column actuator having itsliquid circuit connected to the other chamber, each of said actuatorscyclically developing a pressure greater than the pressure of saidsource, and means for selectively connecting said source to the firstactuator circuit and confining the liquid in the second actuator circuitfor positioning the piston and for confining the liquid in the firstactuator circuit and connecting said source to the second actuatorcircuit for oscillating the end wall means.

6. An oscillator for cyclically moving a part back and forth comprisingin combination a pressure cylinder having movable end wall meansdefining an advancing chamber, a second pressure cylinder having movableend wall means defining a retracting chamber, a source of liquidpressure, a first liquid column actuator having its liquid circuitconnected to one chamber, a second liquid column actuator including animpulse generator and having its liquid circuit connected to the otherchamber, a continuously rotatable operator for the impulse generator,each of said actuators cyclically developing a pressure greater than thepressure of said source, a valve movable to two positions, in one ofwhich it connects said source to the first actuator circuit and confinesthe liquid in the second actuator circuit, and in the other of whichpositions it confines the liquid in the first actuator circuit andconnects said source to the second actuator circuit and means responsiveto the angular position of the operator for moving the valve from oneposition to the other.

7. An oscillator for cyclically moving a part back and forth comprisingin combination a pressure cylinder having movable end Wall meansdefining an advancing chamber, a second pressure cylinder having movableend wall means defining a retracting chamber, a source of liquidpressure, a first liquid column actuator having its liquid circuitconnected to one chamber, a second liquid column actuator including animplse generator and having its liquid circuit connected to the otherchamber, a continuously rotatable operator for the impulse generator,each of said actuators cyclically developing a pressure greater than thepressure of said source, a valve movable to two positions, in the firstof which it connects said source to the first actuator circuit andconfines the liquid in the second actuator circuit, and in the second ofwhich positions it confines the liquid in the first actuator circuit andconnects said source to the second actuator circuit, means constantlyurging the valve member toward the first position, and means responsiveto the angular position of the operator for overcoming the urging meansand holding the valve member in the second position.

'8. An oscillator for cyclically moving a part back and forth comprisingin combination a pressure cylinder having movable end wall meansdefining an advancing chamber a second pressure cylinder having movableend wall means defining a retracting chamber, a source of liquidpressure, an oscillator having its liquid circuit connected to onechamber, a liquid column actuator including an impulse generator andhaving its liquid circuit connected to the other chamber, a continuouslyrotatable operator for the impulse generator, said oscillator andactuator each cyclically developing a pressure greater than the pressureof said source, a casing containing a valve movable to two positions, inone of which it connects said source to the oscillator circuit andconfines the liquid in the actuator circuit for positioning the piston,and in the other of which positions it confines the liquid in theoscillator circuit and connects said source to the actuator circuit foroscillating the end wall means, a piston movable in a pressure cylinderwithin the casing for moving the valve from one position to the other,means constantly urging the valve member toward the first position,means for overcoming the urging means and holding the valve member inthe second position, a second impulse generator driven by the operatorin timed relation to the first impulse generator, and means connectingthe second impulse generator to the valve cylinder for moving the valveagainst the urging means in response to the angular position of theoperator.

9. An oscillator for cyclically moving a part back and forth comprisingin combination a pressure cylinder having movable end Wall meansdefining an advancing chamber, a second pressure cylinder having movableend Wall means defining a retracting chamber, a source of liquidpressure, a first liquid column oscillator having its liquid circuitconnected to one chamber, a liquid column actuator including an impulsegenerator and having its liquid circuit connected to the other chamber,a continuously rotatable operator for the impulse generator, saidoscillator and actuator each cyclically developing a pressure greaterthan the pressure of said source, a valve movable to two positions, inthe first of which it connects said source to the oscillator circuit andconfines the liquid in the actuator circuit for positioning the end wallmeans, and in the second of which positions it confines the liquid inthe oscillator circuit and connects said source to the actuator circuitfor oscillating the end wall means, means responsive to one angularposition of the operator for moving the valve from the first position tothe second, and responsive to another angular position for moving thevalve from the second position to the first, a second oscillator whoseliquid circuit is connected to the liquid circuit of the firstoscillator, an input shaft, means for selectively connecting the inputshaft to either oscillator, and means responsive to connection of theshaft to the second oscillator after movement of the valve to the firstposition for moving the valve to the second position.

10. An oscillator for moving a part back and forth comprising incombination a sealed casing having opposing end chambers eachsurrounding a valve seat and a center chamber containing a ball adaptedto rest on either seat for establishing communication between the centerchamber and one end chamber and preventing communication between thecenter chamber and the other end chamber, means in one end chamberconstantly urging the ball toward the seat of the other end chamber,pressure responsive means in the other end chamber for holding the ballagainst the seat of said one end chamber, and means for selectivelypressurizing and de-pressurizing said pressure responsive means.

11. An oscillator for cyclically moving a part back and forth comprisingin combination an advancing pressure chamber, a retracting pressurechamber, a source of liquid pressure, a first liquid column actuatorhaving its liquid circuit connected to one chamber, a second liquidcolumn actuator having its liquid circuit connected to the otherchamber, each of said actuators cyclically developing a pressure greaterthan the pressure of said source and one of the actuators having adisplacement greater than the maximum volume of the chamber to which itis connected, means for selectively connecting said source to the firstactuator circuit and confining the liquid in the second actuator circuitfor positioning the part and for confining the liquid in the firstactuator circuit and connecting said source to the second actuatorcircuit for oscillating the part, a pressure relief valve fordischarging liquid from one liquid column to the source, and a secondpressure relief valve for discharging liquid from the source to said oneliquid column.

12. An oscillator for cyclically moving a part back and forth comprisingin combination an advancing pressure chamber, a retracting pressurechamber, a source of liquid pressure, a first liquid column actuatorhaving its liquid circuit connected to one chamber, a second liquidcolumn actuator having its liquid circuit connected to the otherchamber, each of said actuators cyclically developing a pressure greaterthan the pressure of said source and one of the actuators having adisplacement greater than the maximum volume of the chamber to which itis connected, means for selectively connecting said source to the firstactuator circuit and confining the liquid in the second actuator circuitfor positioning the part and for confining the liquid in the firstactuator circuit and connecting said source to the second actuatorcircuit for oscillating the part, a pressure relief valve fordischarging liquid from one liquid column to the source, and a secondpressure relief valve for discharging liquid from the source to said oneliquid column including means for limiting the pressure in one liquidcolumn to a predetermined value below the pressure of the source whenthe source is connected to said one column.

13. An oscillator for moving a part back and forth comprising incombination an oscillatable member, a pressure chamber for urging themember in one direction, return means urging the member in the oppositedirection, a first confined liquid column oscillator including a pistonof relatively small displacement connected hydraulically to the chamberfor oscillating the member through a relatively short stroke, a secondconfined liquid column oscillator including a piston of relatively largedisplacement connected hydraulically to the chamber for oscillating themember through a relatively long stroke, the first oscillator developinga pressure whose force in the chamber is alternately above and below theforce of the return means when the second piston is in a predeterminedrange of positions, the second oscillator developing a pressure whoseforce in the chamber is alternately above and below the force of thereturn means regardless of the position of the first piston, firstactuating means for reciprocating the piston of smalldisplacement,second actuating means for reciprocating the piston of largedisplacement, means for driving either actuating means while stoppingthe other actuating means, and means for stopping the second actuatingmeans only when the piston of large displacement is in a predeterminedrange of positions.

14. An oscillator for moving a part back and forth comprising incombination an oscillatable member, a pressure chamber for urging themember in one direction, return means urging the member in the oppositedirection, a pair of confined liquid column oscillators connected inparallel to the chamber each adapted to develop a pressure whose forcein the chamber is alternately above and below the force of the returnmeans, an individual rotary actuator for each oscillator, rotary drivingmeans for driving either actuator, a solenoid for shifting a drivingconnection from one actuator to the other, means for initiating changeof current through the solenoid, a switch for completing the change ofcurrent initiated by said initating means, and a cam on one rotaryactuator for operating the switch when and only when said one rotaryactuator is in a predetermined range of angular positions.

15. An oscillator for moving a part back and forth comprising incombination an oscillatable member, a pressure chamber for urging themember in one direction, return means urging the member in the oppositedirection, a pair of confined liquid column oscillators connected inparallel to the chamber each adapted to develop a pressure whose forcein the chamber is alternately above and below the force of the returnmeans, an individual rotary actuator for each oscillator, rotary drivingmeans for driving either actuator, means for shifting a drivingconnection from one actuator to the other, and means responsive toinitiation of the shift from one of the actuators for delaying thecompletion of the shift until said one actuator is in a predeterminedrange of angular positions.

16. An oscillator for cyclically moving a part back and forth comprisingin combination an advancing pressure chamber, a retracting pressurechamber, a source relatively high liquid pressure, a first liquid columnactuator having its liquid circuit connected to one chamber, a secondliquid column actuator having its liquid circuit connected to the otherchamber, each of said actuators cyclically developing a pressure greaterthan the pressure of said source, means for selectively connecting saidsource to the first actuator circuit and confining the liquid in thesecond actuator circuit for positioning the part and for confining theliquid in the first actuator circuit and connecting said source to thesecond actuator circuit for oscillating the part, a source of relativelylow pressure, balance valve means connecting relatively high pressuresource to one liquid column and balance valve means connecting the lowpressure source to the other liquid column.

17. An oscillator for cyclically moving a part back and forth comprisingin combination an advancing pressure chamber, a retracting pressurechamber, a source of liquid pressure connected to the retractingchamber, a liquid column actuator having its liquid circuit connected tothe advancing chamber, a pressure relief valve for discharging liquidfrom the liquid column to the source and a second pressure relief valvefor discharging liquid from the source to the liquid column.

References Cited UNITED STATES PATENTS 1,944,351 1/1934 Landry 60-545MARTIN P. SCHWADRON, Primary Examiner.

R. R. BUNEVICH, Assistant Examiner.

